commit 7b55984c96ffe9e236eb9c82a2196e0b1f84990d upstream.
Invoking the make_tx_response() / push_tx_responses() pair with no lock
held would be acceptable only if all such invocations happened from the
same context (NAPI instance or dealloc thread). Since this isn't the
case, and since the interface "spec" also doesn't demand that multicast
operations may only be performed with no in-flight transmits,
MCAST_{ADD,DEL} processing also needs to acquire the response lock
around the invocations.
To prevent similar mistakes going forward, "downgrade" the present
functions to private helpers of just the two remaining ones using them
directly, with no forward declarations anymore. This involves renaming
what so far was make_tx_response(), for the new function of that name
to serve the new (wrapper) purpose.
While there,
- constify the txp parameters,
- correct xenvif_idx_release()'s status parameter's type,
- rename {,_}make_tx_response()'s status parameters for consistency with
xenvif_idx_release()'s.
Fixes: 210c34dcd8d9 ("xen-netback: add support for multicast control")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/980c6c3d-e10e-4459-8565-e8fbde122f00@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c7ec4f2d684e17d69bbdd7c4324db0ef5daac26a upstream.
While frontends may submit zero-size requests (wasting a precious slot),
core networking code as of at least 3ece782693c4b ("sock: skb_copy_ubufs
support for compound pages") can't deal with SKBs when they have all
zero-size fragments. Respond to empty requests right when populating
fragments; all further processing is fragment based and hence won't
encounter these empty requests anymore.
In a way this should have been that way from the beginning: When no data
is to be transferred for a particular request, there's not even a point
in validating the respective grant ref. That's no different from e.g.
passing NULL into memcpy() when at the same time the size is 0.
This is XSA-448 / CVE-2023-46838.
Cc: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
